JP2019050107A - Battery, manufacturing method for battery, and electronic apparatus - Google Patents

Abstract

To provide a battery having excellent lithium ion conductivity, and a manufacturing method for the battery capable of manufacturing the battery and an electronic apparatus excellent in reliability.SOLUTION: A battery of the present invention comprises: a current collector; an active material composite body including granular active materials being brought into contact with the current collector and having single crystal structures and a resin part formed in a gap between adjacent active materials; and an electrolyte layer being brought into contact with the resin part and brought into contact with the active materials. The active materials preferably contain LiCoO.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a battery, a method of manufacturing a battery, and an electronic device.

  Lithium secondary batteries are used as power sources for many electric devices including portable information devices. The lithium battery includes a positive electrode, a negative electrode, and an electrolyte layer disposed between the positive electrode and the negative electrode for conducting lithium ions.

  Also, conventionally, liquid electrolytes have been used as electrolytes, but there is concern about safety in liquid electrolytes, and in recent years, as a lithium battery having both high energy density and safety, it is used as a material for forming a solid electrolyte layer Solid state lithium batteries using a solid electrolyte are known (see, for example, Patent Document 1).

  In such a solid type lithium battery, an organic solid electrolyte such as solid polymer electrolyte (SPE) or an inorganic solid electrolyte such as sulfide or oxide is used as an electrolyte.

However, the lithium ion conductivity of a solid electrolyte, particularly an oxide solid electrolyte, is, for example, two to three digits lower than that of a typical electrolyte, such as LiPF ₆ / EC / DEC. . Therefore, it is very difficult to deliver lithium ions to the positive electrode active material on the side close to the positive electrode current collector located far from the negative electrode side, or to extract lithium ions from the positive electrode active material at the same position. Therefore, high C rate characteristics, that is, high-speed charge and discharge characteristics can not be expected, and it has been difficult to say that solid lithium batteries have reached practical levels.

  In order to solve such problems, in Patent Document 2, a plurality of positive electrode active material particles (single crystal particles) constituting an active material plate are arranged and arranged in a lattice shape in the surface direction of a positive electrode current collector. Thus, lithium ions move in one positive electrode active material particle in the thickness direction of the active material plate, and it has been proposed to improve lithium ion conductivity in the active material plate.

  However, in this case, the contact surface between the active material plate and the electrolyte layer is nonuniform due to variations in the shapes and particle sizes of the plurality of positive electrode active material particles constituting the active material plate. It becomes. As a result, it becomes difficult to form an electrolyte layer having a uniform film thickness, and although lithium ion conductivity in the active material plate can be improved, delivery of lithium ions between the active material plate and the electrolyte layer is As a result, the lithium ion conductivity as a whole of the lithium secondary battery is not sufficiently improved.

Unexamined-Japanese-Patent No. 2006-277997 JP, 2014-110240, A

  One of the objects of the present invention is to provide a battery having excellent lithium ion conductivity, a method of manufacturing a battery capable of manufacturing such a battery, and an electronic device having excellent reliability.

Such an object is achieved by the present invention described below.
The battery of the present invention comprises:
An active material complex including a granular active material having a single crystal structure in contact with the current collector, and a resin portion formed in a gap between the adjacent active materials;
And an electrolyte layer in contact with the active material as well as in contact with the resin portion.
Thereby, the battery of the present invention has excellent lithium ion conductivity.

In the battery of the present invention, the active material preferably contains LiCoO ₂ .
Thus, active material particles can be reliably formed of granular active materials having a single crystal structure.

  In the battery of the present invention, the active material complex is preferably in contact with the current collector and the electrolyte on a flat surface.

  Thus, the active material complex can be bonded to the current collector and the electrolyte with excellent adhesion and adhesion.

  In the battery of the present invention, the resin portion is preferably made of an epoxy resin or an acrylic resin.

  Thus, the resin material can be filled in the gaps between adjacent active materials with excellent filling properties.

In the battery of the present invention, the ion conductivity of the resin portion is preferably 1 × 10 ⁻⁸ S / cm or less.

  This makes it possible to be electrochemically stable with respect to the contact with the active material contained in the active material complex and the electrolyte contained in the electrolyte layer.

In the battery of the present invention, the Young's modulus of the resin portion is preferably 15 GPa or less.
As a result, internal stress in the active material complex can be reduced due to the volume change of the active material particles accompanying the movement of lithium (ion).

The method of manufacturing a battery of the present invention comprises the steps of: forming a current collector;
After arranging the active material particles so as to be in contact with the current collector, the resin material is filled in the gaps between the adjacent active material particles to form a resin complex, and after that, the active material particles are exposed. Obtaining an active material complex by polishing to
Forming an electrolyte layer in contact with the exposed active material particles;
And the like.
Thereby, a battery having excellent lithium ion conductivity can be manufactured.

The method for producing a battery of the present invention comprises the steps of: forming an electrolyte layer;
After arranging the active material particles to be in contact with the electrolyte layer, the resin material is filled in the gaps between the adjacent active material particles to form a resin complex, and thereafter, the active material particles are polished to be exposed. Obtaining an active material complex by
Forming a current collector in contact with the exposed active material particles;
And the like.
Thereby, a battery having excellent lithium ion conductivity can be manufactured.

An electronic device of the present invention includes the battery of the present invention.
Thus, the electronic device has excellent reliability.

It is a longitudinal cross-sectional view which shows 1st Embodiment of a lithium secondary battery. It is a flowchart which shows the manufacturing method which manufactures the lithium secondary battery shown in FIG. 1 to process order. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of a lithium secondary battery. It is a flowchart which shows the manufacturing method which manufactures the lithium secondary battery shown in FIG. 13 to process order. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a figure for demonstrating the manufacturing method of the lithium secondary battery shown in FIG. It is a perspective view which shows the structure of the wearable apparatus as an electronic device of this embodiment.

  BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a battery, a method of manufacturing a battery, and an electronic device according to the present invention will be described below with reference to the attached drawings. Note that the drawings used for the description are for convenience of explanation, and the dimensions and ratios of the illustrated components may differ from the actual ones. Further, in the description of the drawings, the upper side of the illustrated drawing is referred to as “upper” and the lower side as “lower”.

  In addition, below, the case where the battery of this invention is applied to the lithium secondary battery 100 which has lithium ion conductivity is demonstrated as a representative.

<Lithium rechargeable battery>
<< First Embodiment >>
FIG. 1 is a longitudinal sectional view showing a first embodiment of a lithium secondary battery (battery of the present invention).

  The lithium secondary battery 100 (battery) includes a positive electrode extraction electrode 7, a positive electrode current collector 1 (current collector), a positive electrode active material complex 5 (active material complex), a solid electrolyte layer 3, and a negative electrode. A portion 6 (electrode) and a negative electrode extraction electrode 8 are stacked in contact with each other in this order. The lithium secondary battery 100 is a so-called solid lithium (ion) secondary battery.

  The positive electrode current collector 1 (current collector) is provided in contact with one surface 51 (one surface) of the positive electrode active material composite 5, and thereby, a positive electrode active material portion which is an example of the active material exposed on the one surface 51. It is in contact with 2. The positive electrode current collector 1 functions as a so-called positive electrode in the lithium secondary battery 100.

  As a forming material (constituent material) of the positive electrode current collector 1, for example, aluminum (Al), copper (Cu), titanium (Ti), zirconium (Zr), tantalum (Ta), niobium (Nb), iron (Fe) ), Cobalt (Co), nickel (Ni), zinc (Zn), chromium (Cr), silicon (Si), germanium (Ge), tin (Sn), indium (In), gallium (Ga), gold (Au) ), Platinum (Pt), iridium (Ir), rhodium (Rh), palladium (Pd), ruthenium (Ru), silver (Ag), molybdenum (Mo), tungsten (W), and magnesium (Mg) And one or more metals selected from the group consisting of elemental metals, and alloys containing two or more metal elements selected from this group.

  The shape of the positive electrode current collector 1 is not particularly limited, and examples thereof include a plate, a foil, and a net. Further, the surface of the positive electrode current collector 1 may be smooth or may have irregularities.

  The thickness of the positive electrode current collector 1 is not particularly limited, but is preferably 0.1 μm or more and 200 μm or less, and more preferably 0.1 μm or more and 50 μm or less. By setting the thickness of the positive electrode current collector 1 in such a range (in particular, in a more preferable range), the unit volume or unit weight of the lithium secondary battery 100 is higher than in the case where the upper limit is exceeded. The battery capacity density can be increased. In addition, if it is less than the lower limit, the sheet resistance value is increased and the electric conduction in the surface direction is prevented, and at the same time the mechanical structural strength is reduced, for example, breakage occurs in the peeling process with the substrate 10 described later It is not realistic because the function as the positive electrode current collector 1 can not be exhibited.

  The positive electrode active material composite 5 (active material composite) includes a positive electrode active material 21 (active material) forming the positive electrode active material portion 2, a binder (binding agent) 22 composed of a resin material, and conductive particles 23. And a resin part 4 containing the above, and is provided between the positive electrode current collector 1 and the electrolyte layer 3 in contact with both of them.

  The positive electrode active material portion 2 includes a plurality of positive electrode active materials 21 (positive electrode active material single crystal particles) formed of positive electrode active material single crystal particles, and is disposed along the surface direction of the positive electrode current collector 1. It is provided in contact with both the positive electrode current collector 1 and the electrolyte layer 3 along the longitudinal direction without crystal grain boundaries of the positive electrode active materials. By making the positive electrode active material part 2 into such a configuration, lithium ions move in one positive electrode active material 21 without grain boundaries in the thickness direction of the positive electrode active material part 2 (positive electrode active material composite 5). It will be (diffuse). As a result, lithium ions can be moved (diffused) more smoothly because there is no hindrance to lithium ion conduction due to grain boundaries. Thereby, lithium ion conductivity in the positive electrode active material 21 (positive electrode active material portion 2) can be further improved.

  The positive electrode active material 21 may be composed of a single crystal, and includes an active material composed of a lithium composite oxide. In the present specification, “lithium composite oxide” is a composite oxide that necessarily contains lithium and is composed of two or more metals as a whole.

Examples of such lithium composite oxides include LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ , LiFePO _{4 and the} like, among which LiCoO ₂ is preferred. Is preferably used. Thus, the positive electrode active material 21 can be reliably formed of granular single crystals having a single crystal structure.

  In addition, some atoms in the crystals of these lithium composite oxides are substituted with other transition metals, typical metals, alkali metals, Group 2 elements including alkaline earth metals, rare earth elements including lanthanoids, chalcogens, halogens, etc. The lithium compound mentioned above is also included in the lithium composite oxide, and a solid solution composed of a plurality of these lithium composite oxides can also be used as a positive electrode active material constituting the positive electrode active material 21.

  By including such a lithium composite oxide, the positive electrode active material 21 transfers electrons between the positive electrode active material 21 and the positive electrode current collector 1, and between the positive electrode active material 21 and the electrolyte layer 3. Delivers lithium (ions) and exhibits the function as an active material.

  The resistivity of the positive electrode active material 21 is preferably 1 kΩcm or less. When the positive electrode active material 21 has such a resistivity, when a lithium battery is formed using the positive electrode active material complex 5, the internal resistance of the battery is lowered and a sufficient output can be obtained. The resistivity can be measured, for example, by adhering a copper foil used as an electrode on the surface of the positive electrode active material portion 2 and performing DC polarization measurement.

The thickness t of the positive electrode active material composite 5 is a size determined by the following relational expression (1), where C is the maximum C rate targeted by the battery operation and D is the lithium ion diffusion coefficient in the positive electrode active material 21. It is preferable to set to a small degree or less, and specifically, if the positive electrode active material having a lithium ion diffusion coefficient of 1 × 10 ⁻⁹ cm ² and the target maximum C rate is 1 C Is preferably about 6 μm (or less), preferably about 10 μm (or less) if the target maximum C rate is 0.3 C, and preferably about 18 μm (or less) if the target maximum C rate is 0.1 C. Or less), if the target maximum C rate is 0.03 C, it is preferably set to about 34 μm (or less). Thereby, the lithium secondary battery 100 can reliably have the target C rate.
t ~ ((3, 600 × D / (α × C)) · · · (1)

  Here, in the above relational expression (1), α is a so-called correction coefficient, and is preferably set to about 5 to 15, and more preferably about 10. In addition, if the thickness of the positive electrode active material composite 5 is a thickness equal to or less than the value determined by the lithium ion diffusion coefficient D of the positive electrode active material and the target C rate according to the above-mentioned relational expression (1), Although battery operation at C rate higher than C rate can be expected, it is preferable to set the thickness as determined by the above-mentioned relational expression (1) also in order to increase battery capacity per unit volume or unit weight. . Further, since the positive electrode active material composite 5 is formed through the polishing and thinning process described later, the thickness of the positive electrode active material composite 5 is preferably 1 μm or more from the viewpoint of mechanical strength.

  The binder (binder) 22 covers at least a part of the surface of the positive electrode active material 21 constituting the positive electrode active material portion 2 and connects adjacent positive electrode active material particles 27 with each other in a method of manufacturing a battery described later. While maintaining the shape of the positive electrode active material molded body 26, it has a function of bonding the positive electrode active material molded body 26 and the positive electrode current collector 1.

  The binder 22 is not particularly limited as long as it is a resin material having mechanical adhesive strength that can connect the positive electrode active materials 21 with one another. For example, polyvinylidene fluoride (PVDF), polyvinylidene fluoride hexafluoropropylene copolymer ( PVDF-HFP), a styrene butadiene copolymer (SBR), carboxymethylcellulose (CMC) etc. are mentioned, It can be used combining 1 type, or 2 or more types in these.

  The thickness of the binder 22 is not particularly limited, but is preferably, for example, 0.1 μm or more and 3 μm or less, and more preferably 0.2 μm or more and 1.5 μm or less. Thereby, the function as the binder 22 can be reliably exhibited.

  The conductive particles 23 are disposed to be attached to the surface of the positive electrode active material 21 constituting the positive electrode active material portion 2, and improve the electron conductivity on the surface of the positive electrode active material 21. It has a function of more smoothly delivering electrons to and from the positive electrode current collector 1.

  The conductive particles 23 are, for example, mainly composed of a conductive auxiliary agent, and the shape of the aggregates of the conductive particles 23 is any shape such as spherical, mesh, scaly, spindle, fiber, needle, etc. The shape of the conductive particles 23 alone is particularly preferably spherical. Thereby, the conductive particles 23 can be reliably attached to the surface of the positive electrode active material 21, and electrons can be conducted on the surface of the positive electrode active material 21 through the attached conductive particles 23 and their aggregates. .

  The conductive aid is not particularly limited. For example, amorphous carbon materials such as carbon black, graphene, carbon nanotubes, nanocarbon materials such as fullerene, gold (Au), platinum (Pt), palladium (Pd) And metal materials (precious metal materials) such as rhodium (Rh), iridium (Ir), ruthenium (Ru), and the like, and one or more of them may be used in combination.

  The resin portion 4 includes (is filled with) a resin material in a space (gap) formed in the positive electrode active material portion 2 to which the adjacent positive electrode active material 21 is connected. It has a function of maintaining the shape of the substance complex 5 and stabilizing it.

  The resin portion 4 is not particularly limited as long as it is a curable resin material having a strength capable of maintaining the shape of the positive electrode active material composite 5, but in particular, an epoxy resin or an acrylic resin is preferably used. By using an epoxy resin or an acrylic resin as a resin material constituting the positive electrode active material complex 5, the resin composite 40 is formed in the step [2A-3] of the method of manufacturing a lithium secondary battery described later. At this time, the resin material can be filled in the voids formed in the positive electrode active material molded body 26 with excellent filling property.

The curable resin material (epoxy resin) constituting the resin portion 4 is electrochemically stable in contact with the positive electrode active material contained in the positive electrode active portion 2 and the solid electrolyte contained in the electrolyte layer 3 And preferably insulating with respect to lithium ion conduction. Specifically, the lithium ion conductivity (σLi) is preferably 1 × 10 ⁻⁸ S / cm or less, and 1 × 10 ⁻¹⁸ S / cm or more and 1 × 10 ⁻⁹ S / cm or less More preferable.

  In addition, the elastic modulus of the resin portion 4 is smaller by one digit or more and relatively soft as compared to the elastic modulus of the positive electrode active material portion 2 (positive electrode active material 21). Therefore, the internal stress in the positive electrode active material complex 5 resulting from the volume change of the positive electrode active material part 2 accompanying lithium in / out can be reduced. In this case, specifically, the elastic modulus of the resin portion 4 is set to a Young's modulus (longitudinal elastic modulus) of preferably 15 GPa or less, more preferably 0.1 GPa or more and 10 GPa or less, or a rigidity (shear modulus) Is preferably 5 GPa or less, more preferably 0.03 GPa or more and 3 GPa or less. Thereby, the said effect can be exhibited more notably.

  In the positive electrode active material composite 5 having the above-described configuration, the resin material is filled in the voids formed in the positive electrode active material molded body 26 in which the plurality of positive electrode active material particles 27 are connected to each other, and polishing described later Contacting the current collector and the electrolyte layer on a flat surface through the step of thinning. That is, in the positive electrode active material composite 5, the one surface 51 of the positive electrode active material composite 5 and the other surface 52 of the positive electrode active material composite 5 are formed, and both the one surface 51 and the other surface 52 are flat. As a result, the positive electrode active material composite 5 is joined with excellent adhesion and adhesion to both the positive electrode current collector 1 in contact at the one surface 51 and the electrolyte layer 3 in contact at the other surface 52. It becomes a thing.

  In such a positive electrode active material complex 5, the positive electrode active material 21 composed of a granular active material having a single crystal structure is exposed on both the first surface 51 and the other surface 52. As a result, the positive electrode active material 21 penetrates from one surface 51 to the other surface 52 of the positive electrode active material composite 5 without crystal grain boundaries of the positive electrode active materials. As a result, the positive electrode active material 21 is in contact with the positive electrode current collector 1 on the one surface 51 of the positive electrode active material composite 5 and in contact with the electrolyte layer 3 on the other surface 52 of the positive electrode active material composite 5. Therefore, delivery of lithium ions between the positive electrode active material 21 (positive electrode active material portion 2) and the electrolyte layer 3 and electrons between the positive electrode active material 21 (positive electrode active material portion 2) and the positive electrode current collector 1 Delivery can be done smoothly. At the same time, in the positive electrode active material complex 5, there is no crystal grain boundary between the positive electrode active materials in the thickness direction. Therefore, the lithium secondary battery 100 including the positive electrode active material complex 5 having such a configuration is excellent Can have lithium ion conductivity.

  The electrolyte layer 3 uses a solid electrolyte material having lithium ion conductivity as a forming material (constituent material), and is positioned on the opposite side of the negative electrode portion 6 of the positive electrode active material composite 5 to make the positive electrode active material composite 5 In contact with the other surface 52 (the other surface), and in contact with the resin portion 4 exposed on the other surface 52, and in contact with the positive electrode active material 21 (the positive electrode active material portion 2) It is in contact with the negative electrode portion 6 on the opposite side of the substance complex 5. The electrolyte layer 3 receives a lithium ion from the positive electrode active material portion 2 at the time of charge, and then conducts the lithium ion in the electrolyte layer 3 before passing it to the negative electrode portion 6 at the time of discharge. It has a function of receiving lithium ions from the portion 6 and then transferring the lithium ions to the positive electrode active material portion 2 after being conducted in the electrolyte layer 3.

The electrolyte material may be either a solid polymer electrolyte material (SPE) or an inorganic solid electrolyte material. Examples of the solid polymer electrolyte include polyethylene oxide (PEO) -based solid polymer electrolytes in which a lithium salt is dissolved. Moreover, as an inorganic solid electrolyte material, for example, LIPON (Li ₃ (PO _4-x N _x )), LBO (Li ₃ BO ₃ ), LCBO (Li _{2 + x} C _1-x B _x O ₃ ), Li ₂ CO ₃ , Li ₇ La ₃ Zr ₂ O ₁₂ system, (Li, La) TiO ₃ system, LATP (Li _{1 + x} Al _x Ti _2-x (PO ₄ ) ₃ ) system, LAGP (Li _{1 + x} Al _x Ge _2-x) (PO ₄ ) ₃ ) system, LISICON (Li _{2 + 2 ×} Zn _1−x GeO ₄ ), and other lithium oxoacid salts. Furthermore, the thing of the system which added the suitable element to these materials can also be used as an inorganic solid electrolyte material.

The ion conductivity (σLi) of the electrolyte layer 3 is preferably 1 × 10 ⁻⁶ S / cm or more, more preferably 1 × 10 ⁻⁵ S / cm or more, and further preferably 1 × 10 ⁻⁴ S It is more preferable that it is / cm or more. By the electrolyte layer 3 having such an ion conductivity, the movement of lithium ions between the positive electrode active material portion 2 and the negative electrode active material portion 61 described later is smoothly performed, and the inside of the lithium secondary battery 100 is obtained. Resistance can be reduced, and battery operation at high C-rate can be made more reliable.

  The ion conductivity of the electrolyte layer 3 can be determined, for example, by forming lithium as an electrode on both sides of a thin plate sample made of the material constituting the electrolyte layer 3 by vacuum evaporation as a electrode, or compressing lithium foil and performing an alternating current impedance method. It can measure by doing.

The thickness of the electrolyte layer 3 is not particularly limited, but is preferably, for example, 1 μm to 50 μm, more preferably 1 μm to 10 μm, and still more preferably 1 μm to 3 μm. By setting the thickness of the electrolyte layer 3 within such a range, for example, when the lithium ion conductivity is 1 × 10 ⁻⁵ S / cm and the thickness is 10 μm or less, the resistance of the electrolyte layer 3 per unit area can be calculated. It can be set to 100 Ω cm ² or less. Thereby, lithium ions can be more smoothly transferred from the positive electrode active material portion 2 to the negative electrode portion 6 via the electrolyte layer 3 and from the negative electrode portion 6 to the positive electrode active material portion 2. In addition, since the electrolyte layer 3 is formed on the positive electrode active material complex 5 which has been subjected to the polishing and thinning process as described later, it is possible to prevent a short circuit between the positive electrode active material portion 2 and the negative electrode portion 6. And preferably have a thickness of 1 μm or more.

  The negative electrode portion 6 (electrode) is in contact with the electrolyte layer 3 on the surface opposite to the surface in contact with the other surface 52 of the positive electrode active material composite 5 of the electrolyte layer 3. As shown in FIG. 1, the negative electrode portion 6 includes a negative electrode active material portion 61 and a negative electrode current collector 63. The negative electrode portion 6 receives lithium ions from the electrolyte layer 3 at the time of charge, and passes the lithium ions to the electrolyte layer 3 at the time of discharge.

  The negative electrode active material portion 61 is provided in contact with the negative electrode current collector 63 (negative electrode current collector), and is in contact with the electrolyte layer 3 on the opposite side of the negative electrode current collector 63.

As a forming material (constituent material) of the negative electrode active material portion 61, for example, lithium (Li), lithium alloy, silicon (Si), germanium (Ge), tin (Sn), lithium nitride (Li _3-x M _x N), transition metal oxides or transition metal complex oxides, tin oxides or tin complex oxides, lithium titanate (Li ₄ Ti ₅ O ₁₂ ), carbon-based materials represented by graphite, etc. It is preferable that it is lithium (Li). Since lithium (metal lithium) has a high theoretical capacity density per unit volume or unit weight, the use of a small amount relative to the volume or weight of the positive electrode active material portion 2 is sufficient, so the capacity density of the lithium secondary battery 100 The negative electrode active material portion 61 is preferably used.

  The thickness of the negative electrode active material portion 61 is not particularly limited, but is preferably, for example, 1 μm or more and 100 μm or less, and more preferably 2 μm or more and 50 μm or less.

  The negative electrode current collector 63 (negative electrode collector electrode) is provided in contact with the negative electrode active material portion 61, and is in contact with the negative electrode extraction electrode 8 on the opposite side of the negative electrode active material portion 61.

  As a forming material (constituent material) of the negative electrode current collector 63, for example, copper (Cu), aluminum (Al), titanium (Ti), zirconium (Zr), tantalum (Ta), niobium (Nb), iron (Fe) ), Cobalt (Co), nickel (Ni), zinc (Zn), chromium (Cr), silicon (Si), germanium (Ge), tin (Sn), indium (In), gallium (Ga), gold (Au) ), Platinum (Pt), iridium (Ir), rhodium (Rh), palladium (Pd), ruthenium (Ru), silver (Ag), molybdenum (Mo), tungsten (W), and magnesium (Mg) And one or more metals selected from the group consisting of elemental metals, and alloys containing two or more metal elements selected from this group.

  The positive electrode extraction electrode 7 and the negative electrode extraction electrode 8 are provided on the positive electrode current collector 1 and the negative electrode portion 6 on the opposite side to the positive electrode active material composite 5 and the electrolyte layer 3 respectively, from the respective current collectors It functions as an electrode for extracting current to the outside.

  Examples of materials (constituting materials) for forming the positive electrode extraction electrode 7 and the negative electrode extraction electrode 8 include nickel (Ni), aluminum (Al), copper (Cu), stainless steel, iron (Fe), titanium (Ti), and zirconium. (Zr), tantalum (Ta), niobium (Nb), cobalt (Co), zinc (Zn), chromium (Cr), tin (Sn), gold (Au), platinum (Pt), iridium (Ir), rhodium (A single metal) selected from the group consisting of (Rh), palladium (Pd), ruthenium (Ru), silver (Ag), molybdenum (Mo), tungsten (W), and 2 selected from this group An alloy containing at least a kind of metal element, a laminated material made of two or more kinds of metal elements selected from this group, or a steel material plated with a base metal or a noble metal selected from this group, etc. It is.

  The thickness of the positive electrode extraction electrode 7 and the negative electrode extraction electrode 8 is not particularly limited, but is preferably, for example, 0.01 mm or more and 1 mm or less, and more preferably 0.01 mm or more and 0.5 mm or less.

  The lithium secondary battery 100 of the first embodiment having such a configuration can be manufactured by the following manufacturing method (method of manufacturing the battery of the present invention).

(Method of manufacturing lithium secondary battery)
FIG. 2 is a flow chart showing in order of steps the method of manufacturing the lithium secondary battery shown in FIG. 1 (the method of manufacturing the battery of the present invention), and FIGS. 3 to 12 show the method of manufacturing the lithium secondary battery shown in FIG. It is a figure for demonstrating.

  In addition, each manufacturing process for manufacturing the lithium secondary battery 100 described below is in a dry room (for example, a dew point of −40 ° C. or less) in which the moisture content is set low, under an atmosphere of dry air, or argon It is preferable to carry out in the glove box (For example, dew point is -80 degrees C or less) under atmosphere of inert gas like these.

  [1A] First, the substrate 10 is prepared, and then the positive electrode current collector 1 (collector electrode) is formed on the substrate 10 (step S1A).

[1A-1] First, the substrate 10 is prepared (see FIG. 3).
The substrate 10 supports the positive electrode current collector 1 formed (laminated) on the substrate 10 and the positive electrode active material composite 5 formed in the next step [2A].

The constituent material of the substrate 10 is not particularly limited as long as it can impart mechanical strength capable of supporting the positive electrode current collector 1 and the positive electrode active material composite 5 to the substrate 10, for example, quartz glass, no Inorganic glass materials such as alkali glass, soda lime glass, borosilicate glass, or inorganic ceramic materials such as alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), magnesia (MgO), mullite, polyethylene terephthalate (PET) , Resin materials such as polyethylene naphthalate (PEN), polypropylene (PP), cycloolefin polymer (COP), polyimide (PI), polyether sulfone (PES), polymethyl methacrylate (PMMA), polycarbonate (PC), etc. And one or more of these In combination it can be used.

  The average thickness of such a substrate 10 is not particularly limited, but in the case of an inorganic glass material or inorganic ceramic material which is hard and has high mechanical strength, it is preferably about 0.1 mm or more and 5 mm or less, 0.2 mm or more More preferably, it is about 3 mm or less. If it is a resin material softer than inorganic glass or inorganic ceramic material, it is preferable that it is about 0.2 mm or more and 10 mm or less, and more preferably about 0.5 mm or more and 5 mm or less. As described later, since the substrate 10 is a substrate for supporting the positive electrode active material molded body 26 and obtaining a positive electrode active material complex by the polishing and thinning steps, the relationship formula (1) is used. It is preferable to have flatness (surface roughness) of 1/10 or less of the final thickness t of the positive electrode active material composite 5 shown.

  [1A-2] Next, the positive electrode current collector 1 is formed on the substrate 10 in a state in which a peeling layer (not shown) is interposed (see FIG. 4).

  For example, after the liquid material for forming the peeling layer is supplied onto the substrate 10, the positive electrode current collector 1 is formed after the plate-like, foil-like, net-like, etc. positive electrode current collector 1 is disposed. And by drying the liquid material.

  In addition, the release layer is cured by irradiation with energy rays, dissolved by contact (impregnation) with a solvent, or foamed by heating to form a release layer (not shown) whose adhesive strength is reduced. Is preferred. Thereby, in the post-process [3A], the laminate of the positive electrode current collector 1 and the positive electrode active material complex 5 is easily obtained from the substrate 10 by irradiation of energy rays, contact (impregnation) of solvent with heating to the peeling layer Can be peeled off.

  After the formation of the positive electrode current collector 1 on the substrate 10, it is preferable that the surface of the positive electrode current collector 1 opposite to the substrate 10 be subjected to a cleaning treatment.

  The cleaning process may be either a liquid cleaning process using an organic solvent or a dry cleaning process, but for example, after being subjected to the liquid cleaning process, a dry cleaning process such as UV ozone treatment or atmospheric pressure plasma treatment A combined treatment to apply is preferably used.

  Here, as described above, the thickness of the positive electrode current collector 1 is preferably 0.1 μm to 200 μm, and more preferably 1 μm to 50 μm. In particular, in the state of the positive electrode current collector 1 alone without the substrate 10 functioning as a support having a thickness of 1 μm to 50 μm, which is a more preferable range, for forming the positive electrode active material composite 5 in the next step [2A]. It is not possible to impart mechanical strength sufficient to endure, and in the next step [2A], there arises a problem that the positive electrode current collector 1 is broken. Therefore, prior to the next step [2A], in the present step [1A], the positive electrode current collector 1 is formed on the substrate 10 functioning as a support substrate, so that the thickness of the positive electrode current collector 1 is 1 μm or more. Even if the thickness is set to 50 μm or less, the positive electrode current collector 1 can be reliably formed in the next step [2A] without causing breakage.

  When the thickness of the positive electrode current collector 1 is set to more than 50 μm (for example, more than 50 μm and 200 μm or less), the mechanical strength of the positive electrode current collector 1 itself can only withstand the next step [2A]. Can be granted. Therefore, the formation of the positive electrode current collector 1 on the substrate 10 in this step [1A], and the laminate of the positive electrode current collector 1 and the positive electrode active material composite 5 from the substrate 10 in the post step [3A] Peeling can also be omitted.

  [2A] Next, the positive electrode active material composite 5 (positive electrode active material mixture layer) is formed on the positive electrode current collector 1 (step S2A).

  [2A-1] First, a slurry 25 containing positive electrode active material particles 27, a binder (binding agent), conductive particles 23, and a solvent is supplied onto the positive electrode current collector 1 (see FIG. 5).

  At this time, in the slurry 25 on the positive electrode current collector 1, the plurality of positive electrode active material particles 27 do not overlap each other in the thickness direction in a lattice shape (matrix shape) in the surface direction of the positive electrode current collector 1. Slurry 25 is supplied to be arranged side by side.

  As the solvent, for example, N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), acetonitrile, or alcohol solvents such as methanol, ethanol, isopropanol, butanol, Or methyl ethyl ketone (MEK), diethyl ketone, methyl isopropyl ketone (MIPrK), methyl isobutyl ketone (MIBK), ketone solvents such as acetylacetone, cyclohexanone, or ethyl methyl carbonate (EMC), diethyl carbonate (DEC), propylene carbonate ( Organic solvents such as carbonate solvents such as PC) and the like can be mentioned, and one or two or more of them can be used in combination.

  Further, the positive electrode active material 21 composed of a single crystal can be manufactured, for example, by a crystal growth method such as a known flux method, and also manufactured by a method described in JP-A-2017-91665 or the like. Can.

The average particle diameter (size φ) of the positive electrode active material 21 composed of single crystals is that the positive electrode active material composite 5 is formed by polishing and thinning in a later step [2A-4]. In consideration of the above, the size about twice as large as the thickness t of the finally formed positive electrode active material composite 5 represented by the aforementioned relational expression (1), that is, the following relational expression (2 It is preferable to satisfy Specifically, for example, if the lithium ion diffusion coefficient of the positive electrode active material is 1 × 10 ⁻⁹ cm ² / s, and the target maximum C rate is 1 C, the target maximum C rate is approximately 12 μm, 0 If it is 3C, about 21 μm, if the target maximum C rate is 0.1 C, about 37 μm, if the target maximum C rate is 0.03 C, about 69 μm is preferable. Thus, by polishing and thinning, the positive electrode active material composite 5 having the target (final) thickness t can be reliably formed.
φ ~ 2 × √ (3, 600 × D / (α × C)) · · · (2)

  The positive electrode active material 21 to be used is preferably classified by using a sieve or the like so as to have the above-mentioned size, and preferably has a narrow particle size distribution with a half width.

  Further, the supply of the slurry 25 onto the positive electrode current collector 1 is performed so that the thickness of the supplied slurry 25 (coated film) becomes substantially equal to the particle size (size φ) of the positive electrode active material particles 27. Is preferred. Thereby, the positive electrode active material molded body 26 formed in the next step [2A-2] is arranged by arranging a plurality of positive electrode active material particles 27 in a lattice shape (matrix shape) in the surface direction of the positive electrode current collector 1 That is, the plurality of positive electrode active material particles 27 constituting the positive electrode active material molded body 26 can be arranged (dispersed) in a single layer (one layer) state without stacking in the thickness direction.

  The weight ratio of the positive electrode active material particles 27 to the binder and the conductive particles 23 is preferably 80:10:10 to 98: 1: 1, more preferably about 90: 5: 5. It is preferable to prepare the slurry 25.

  [2A-2] Next, the supplied slurry 25 is dried to form the positive electrode active material molded body 26 on the positive electrode current collector 1 (see FIG. 6).

  Drying of the slurry 25 desolvates the solvent contained in the slurry 25. As a result, the binder 22 covers at least a part of the surface of the positive electrode active material particles 27, whereby adjacent positive electrode active material particles 27 and the positive electrode active material particles 27 and the positive electrode current collector 1 are connected. Ru. Thereby, the plurality of positive electrode active material particles 27 are formed in a state in which the positive electrode active material molded body 26 having a configuration in which the plurality of positive electrode active material particles 27 are arranged in a single layer without being stacked Ru.

  In addition, at the time of forming the positive electrode active material molded body 26, the conductive particles 23 are formed to be attached to the surface of the positive electrode active material particles 27.

  The drying of the slurry 25 is carried out, for example, by heating it for about 1 hour or more, preferably 24 hours or more, at a heating temperature of about 120 ° C. on a hot plate under a dry air or a reduced pressure atmosphere or in an oven.

  [2A-3] Next, in the positive electrode active material molded body 26, a resin molded body 41 made of a curable resin material in which a curable resin material is filled in the gaps formed between the positive electrode active material particles 27 is formed. Then, a resin composite 40 including the positive electrode active material molded body 26 and the resin molded body 41 is formed (see FIG. 7).

  In this case, as shown in FIG. 7, the resin composite 40 is shown without exposing the upper surface of the positive electrode active material molded body 26 having a configuration in which a plurality of positive electrode active material particles 27 are arranged in a single layer. The resin molded body 41 is formed to cover the whole of the positive electrode active material molded body 26.

  As a resin material for forming the resin molded body 41, an epoxy resin or an acrylic resin (in particular, an electronic device, a ceramic / metal material, or a rock / mineral sample or the like used in sample preparation for microstructure observation) Embedded resin materials such as epoxy resin) are preferably used. This is because, when the embedded resin material is impregnated with the precursor solution of the embedded resin material in the space formed between the positive electrode active material particles 27, the embedded resin material is completely removed by a method such as vacuum impregnation. The precursor solution can be distributed, so that after polymerization and curing, it can be embedded without leaving voids and filled with the resin material.

  Therefore, below, the case where the resin complex 40 comprised with an epoxy resin is formed is demonstrated to an example.

  First, dry cleaning treatment such as UV ozone treatment or atmospheric pressure plasma treatment is applied to the positive electrode active material molded body 26 to form a gap formed on the surface of the positive electrode active material particles 27 and between the positive electrode active material particles 27. The surface of the positive electrode current collector 1 exposed from the surface is cleaned.

Next, an epoxy resin precursor for filling the voids provided in the positive electrode active material molded body 26 by mixing triethylenetetramine as a curing agent into a resin raw material consisting of bisphenol A · epichlorohydrin and an oxylene monoalkyloxy derivative. Prepare body solution. Then, by supplying the epoxy resin precursor solution to the positive electrode active material molded body 26, the voids provided in the positive electrode active material molded body 26 are filled with the epoxy resin precursor solution. Then, the resin composite 40 is formed by curing the epoxy resin precursor solution at room temperature for 1 hour or more, preferably 24 hours or more. Note that these steps are preferably performed in a reduced pressure atmosphere. Thereby, the generation of air bubbles inside the resin composite 40 to be formed can be accurately suppressed or prevented, and the resin material can be filled up to every corner without leaving a void between the positive electrode active material particles 27. .
The resin complex 40 is formed through the above steps.

  In the formation of the resin composite 40, the resin molded body 41 is filled with the resin material in the space formed between the positive electrode active material particles 27 in the positive electrode active material molded body 26. It is formed. Thereby, the one surface 51 formed in contact with the positive electrode current collector 1 is constituted by a flat surface, and on this one surface 51, the positive electrode current collector 1 comprises the positive electrode active material molded body 26 and the resin molded body 41. Contact both sides.

  Further, since the positive electrode active material portion 2 and the resin portion 4 are sequentially formed on the positive electrode current collector 1 using the method described above, the positive electrode active material portion 2 and the resin portion 4 are formed on the surface 51. Both are formed with excellent adhesion and adhesion.

  [2A-4] Then, grinding and polishing the upper surface of the resin molded body 41 for filling and covering between the positive electrode active material particles 27 with each other from the resin complex 40 to the positive electrode active material molded body 26 (positive electrode active material The top surface of the particle 27) is exposed (see FIG. 8).

  Thereby, the upper surface of the positive electrode active material molded body 26 is exposed from the resin composite 40 on the positive electrode current collector 1, and as a result, the plurality of positive electrode active materials 21 constituting the positive electrode active material portion 2 have uniform heights. In the aligned state, one positive electrode active material 21 penetrates from the positive electrode current collector 1 to the other surface 52 which is the upper surface (uppermost surface) of the positive electrode active material complex 5, and The positive electrode active material composite 5 having a configuration in which the resin material is filled in the void formed between the two is formed. At this time, the other surface 52 (the other surface) of the positive electrode active material composite 5 is formed as a flat surface, and further on the surface, a scratch mark (grinding mark and polishing mark) which is a trace of grinding and polishing ) Is left.

  Here, in the present step, grinding and polishing (polishing and thinning) of the upper surface of the resin composite 40 (the resin molded body 41) are performed, and the thickness of the resin composite 40 is the average particle diameter of the positive electrode active material particles 27. Implement until it becomes about half or less. Thereby, positive electrode active material composite 5 including positive electrode active material portion 2 (positive electrode active material 21) and resin portion 4 in which the upper surface of positive electrode active material molded body 26 is reliably exposed from resin portion 4 can be obtained. . Under the present circumstances, since the resin material is filled in the space | gap formed between positive electrode active material 21 comrades and stabilization of the mechanical strength of the resin composite 40 is achieved, grinding and grinding | polishing of the resin composite 40 are carried out. Can be easily implemented. Further, since grinding and polishing are performed until the average particle diameter of the positive electrode active material particles 27 is equal to or less than that, the heights of the respective positive electrode active material particles 27 can be made uniform.

  Specifically, the final thickness t of the positive electrode active material composite 5 by grinding / polishing is the average particle diameter φ of the positive electrode active material particles 27 before grinding, that is, the thickness of the positive electrode active material molded body 26 before grinding. On the other hand, it is preferably set to 20% or more and 80% or less, more preferably 40% or more and 60% or less, and further preferably about 50%. Here, as described above, the average particle diameter φ of the positive electrode active material particles 27 satisfies the relational expression (2). Therefore, by setting the final thickness t of the positive electrode active material composite 5 by grinding and polishing within the above range, the final thickness t of the positive electrode active material composite 5 satisfies the relation (1). Since the obtained lithium secondary battery 100 can reliably have the target C rate.

The method for grinding and polishing (polishing and thinning) the upper surface of the resin composite 40 is not particularly limited, but the wet polishing method and the dry polishing method are preferably the dry polishing method. In the case of the dry polishing method, an abrasive film sheet in which abrasive grains such as SiC fine powder and Al ₂ O ₃ fine powder are embedded in a polymer film is used, and the abrasive grains are dispersed in a liquid such as water or an organic solvent Since the polishing can be performed without using the polishing slurry thus made, it is possible to properly prevent the deterioration of the positive electrode active material composite 5, particularly the chemical damage to the positive electrode active material.

  Further, in the case of using the dry polishing method, it is preferable to perform the polishing environment in a dry room with extremely low moisture content in the atmosphere or in a glove box filled with an inert gas such as dry air or argon. In this case, first, the resin composite 40 is polished using an abrasive film sheet having a coarse grain. Then, while gradually changing to fine-grained abrasive film sheets, the other surface 52 of the positive electrode active material complex 5 is finished as a mirror surface as possible. Then, surface particles (abrasive debris) remaining on the other surface 52 are removed by dry air blowing or inert gas blowing. If surface particles can not be sufficiently removed by this blow, ultrasonic cleaning may be performed with an organic solvent, the solvent may be removed by the blow, and then drying may be performed on an oven or a hot plate. Furthermore, in the mirror surface treatment step of the final polishing, the polishing treatment may be performed by a vacuum dry etching process such as ion milling.

  According to the above steps [2A-1] to [2A-4], a plurality of granular positive electrode active material particles 27 (active material particles) having a single crystal structure and in contact with the positive electrode current collector 1 (collector electrode) After forming the positive electrode active material molded body 26 (active material molded body), the resin material is filled in the gap between adjacent positive electrode active material particles 27 to form the resin composite 40, and then, from the resin composite 40 to the positive electrode. A step of obtaining the positive electrode active material complex 5 (active material complex) is configured by polishing so that the active material particles 27 are exposed, and the positive electrode active material can be formed on the positive electrode current collector 1 through such steps. Complex 5 is formed.

  [3A] Next, as shown in FIG. 9, the substrate 10 is peeled off from the positive electrode current collector 1 (step S3A).

  Peeling of the substrate 10 from the positive electrode current collector 1 may be like ultraviolet light from the substrate 10 side according to the type of peeling layer (not shown) formed between the positive electrode current collector 1 and the substrate 10. Irradiating the release layer with an energy beam, bringing the solvent into contact (impregnation) with the release layer from between the substrate 10 and the positive electrode current collector 1, or heating the release layer from the substrate 10 side It is carried out by selecting

  In the present embodiment, the peeling of the substrate 10 from the positive electrode current collector 1 is performed after the formation of the positive electrode active material complex 5 described in the above step [2A], but the present invention is limited thereto. Instead, for example, it may be performed after the formation of the electrolyte layer 3 described in the next step [4A] or after the formation of the negative electrode portion 6 described in the next step [5A].

  [4A] Next, as shown in FIG. 10, the electrolyte layer 3 is formed on the positive electrode active material complex 5 so as to be in contact with the positive electrode active material 21 exposed by the positive electrode active material complex 5 (step S4A).

When the electrolyte layer 3 is configured to include a solid polymer electrolyte material (SPE), the electrolyte layer 3 may be, for example, LiTFSI (Li (CF ₃ SO ₂ ) ₂ N), Li (Li (FSO ₂ )) ₂ N), LiC ₄ F ₉ SO ₃ , LiTFS (LiCF ₃ SO ₃ ), LiPF ₆ , LiBF ₆ , LiClO _{4 and the} like are used to prepare a precursor in which a lithium salt is dissolved, and then this precursor is After depositing on the positive electrode active material composite 5, it can be obtained by polymerizing and curing the precursor with ultraviolet light or heat. In addition to the above method, the electrolyte layer may also be formed by mechanically pressing the electrolyte layer 3 composed of a solid polymer electrolyte material in the form of a film separately prepared as a separate body onto the positive electrode active material composite 5. 3 can be formed.

  When the electrolyte layer 3 includes the inorganic solid electrolyte material, the electrolyte layer 3 can be relatively easily formed by using the sputtering method.

  Preferably, the other surface 52 of the positive electrode active material complex 5 is reverse sputtered prior to the formation of the electrolyte layer 3. Thereby, in the step [2A], the damaged layer remaining on the surface of the other surface 52 formed by grinding and polishing can be removed. Therefore, lithium ions can be more smoothly delivered between the electrolyte layer 3 and the positive electrode active material portion 2 (positive electrode active material 21) on the other surface 52.

  As described above, since the electrolyte layer 3 is formed on the other surface 52 formed of the flat surface, the degree of adhesion of the electrolyte layer 3 to the positive electrode active material complex 5 on the other surface 52 is excellent. It is formed with

  [5A] Next, as shown in FIG. 11, the negative electrode portion 6 in contact with the electrolyte layer 3 is formed on the electrolyte layer 3 (step S5A).

  The formation of the negative electrode portion 6 is performed by forming the negative electrode active material portion 61 and then forming the negative electrode current collector 63.

  For example, lithium (metallic lithium) can be used as the constituent material of the negative electrode active material portion 61. In this case, the negative electrode active material portion 61 is preferably formed on the electrolyte layer 3 by vacuum evaporation. Alternatively, a method of mechanically pressing a lithium (metallic lithium) foil to the electrolyte layer 3 can also be used.

  Lithium metal is a very active metal and reacts not only with water but also with nitrogen. Therefore, the subsequent steps including the present step [5A] are preferably performed in an environment filled with a rare gas such as argon and having a low water content, for example, in a glove box.

Next, the negative electrode current collector 63 is formed on the negative electrode active material portion 61 (see FIG. 11).
Copper (Cu) is suitably used as a material of which the negative electrode current collector 63 is made. The negative electrode current collector 63 can use, for example, physical vapor deposition such as vacuum evaporation or sputtering, and can use a plate-like, foil-like, net-like, etc. negative electrode current collector 63 as a negative electrode. The active material portion 61 may be mechanically pressure-bonded.

  [6A] Next, as shown in FIG. 12, the positive electrode extraction electrode 7 and the negative electrode extraction electrode 8 are formed on the positive electrode current collector 1 and the negative electrode portion 6, respectively (Step S6A).

  For forming the positive electrode extraction electrode 7 and the negative electrode extraction electrode 8, for example, a metal plate (electrode plate) or a metal foil made of the above-described metal, alloy or the like is prepared. It can implement by joining to the part 6, respectively. In addition to this method, in a state in which the metal plate or the metal foil is a laminate disposed on each of the positive electrode current collector 1 and the negative electrode portion 6, the laminate is a polymer film such as aluminum and PET. It can also be a method of sealing with an aluminum multilayer film consisting of a multilayer structure of

  Through the steps [1A] to [6A] as described above, the lithium secondary battery 100 of the present embodiment having excellent lithium ion conductivity is manufactured.

<< Second Embodiment >>
Next, a second embodiment of the lithium secondary battery 100 will be described.
FIG. 13 is a longitudinal sectional view showing a second embodiment of the lithium secondary battery.

  Hereinafter, the lithium secondary battery 100 of the second embodiment will be described focusing on differences from the lithium secondary battery 100 of the first embodiment, and the description of the same matters will be omitted.

  The lithium secondary battery 100 shown in FIG. 13 is the same as the lithium secondary battery 100 shown in FIG. 1 except that the configuration of the positive electrode active material complex 5 included in the lithium secondary battery 100 is different.

  That is, in the lithium secondary battery 100 of the second embodiment, the positive electrode active material complex 5 is the same as the lithium secondary battery 100 of the first embodiment, from the positive electrode current collector 1 to the upper surface of the positive electrode active material complex 5 One positive electrode active material 21 penetrates to the other surface 52 which is the (uppermost surface), and the space formed between the positive electrode active materials 21 is filled with a resin material. However, unlike the lithium secondary battery 100 according to the first embodiment, abrasion marks (grinding and grinding marks) are not on the other surface 52 of the positive electrode active material composite 5 but on the surface 51 (one surface).・ Polishing marks are left. Also by the lithium secondary battery 100 of the second embodiment, the same effect as that of the first embodiment can be obtained.

  The lithium secondary battery 100 of the second embodiment having such a configuration can be manufactured by the following manufacturing method (the manufacturing method of the battery of the present invention).

(Method of manufacturing lithium secondary battery)
FIG. 14 is a flowchart showing in order of steps the method of manufacturing the lithium secondary battery shown in FIG. 13 (the method of manufacturing the battery of the present invention), and FIGS. 15 to 24 are methods of manufacturing the lithium secondary battery shown in FIG. It is a figure for demonstrating.

  [1B] First, the substrate 10 is prepared (see FIG. 15), and then the electrolyte layer 3 is formed on the substrate 10 as shown in FIG. 16 (step S1B).

  As the substrate 10, the same one as described in the step [1A-1] is used, and by using the same method as the one described in the step [4A] on the substrate 10, The electrolyte layer 3 is formed.

  Here, as described above, the thickness of the electrolyte layer 3 is preferably set in the range of 1 μm to 50 μm, and more preferably in the range of 1 μm to 10 μm. In particular, at a thickness of 1 μm to 10 μm, which is a more preferable range, the electrolyte layer 3 can not be provided with mechanical strength sufficient to withstand formation of the positive electrode active material composite 5 in the next step [2B]. In the next step [2B], there arises a problem that the electrolyte layer 3 is broken. Therefore, prior to the next step [2B], in the present step [1B], the electrolyte layer 3 is formed on the substrate 10 functioning as a supporting substrate, so that the thickness of the electrolyte layer 3 is 1 μm to 10 μm. Even if the thickness is set to be thin, the electrolyte layer 3 can be reliably formed in the next step [2B] without causing breakage.

  When the thickness of the electrolyte layer 3 is set to more than 100 μm, mechanical strength sufficient to withstand the next process [2B] can be given to the electrolyte layer 3 itself. Therefore, the formation of the electrolyte layer 3 on the substrate 10 in the present step [1B] and the peeling of the laminate of the electrolyte layer 3 and the positive electrode active material complex 5 from the substrate 10 in the subsequent step [4B] are omitted. It can also be done.

  When the formation of the electrolyte layer 3 on the substrate 10 in the present step [1B] is omitted, a solid electrolyte film composed of a solid polymer electrolyte material is preferably used as the electrolyte layer 3.

[2B] Next, the positive electrode active material complex 5 is formed on the electrolyte layer 3 (step S2B).
[2B-1] First, the positive electrode active material particles 27, the binder (binding agent), and the conductive particles 23 are formed on the electrolyte layer 3 using the same method as that described in the step [2A-1]. And a solvent containing a slurry 25 (see FIG. 17).

  [2B-2] Next, the positive electrode active material molded body 26 is formed on the electrolyte layer 3 by drying the supplied slurry 25 in the same manner as described in the step [2A-2]. 18).

  [2B-3] Next, in the positive electrode active material molded body 26, in the same manner as described in the step [2A-3], in the voids formed between the positive electrode active material particles 27, a curable resin material A resin molded body 41 made of a curable resin material filled with is formed, and a resin composite 40 including the positive electrode active material molded body 26 and the resin molded body 41 is formed (see FIG. 19).

  [2B-4] Then, in the same manner as described in the step [2A-4], a resin composite is obtained by grinding and polishing the upper surface of the resin material filling and covering the positive electrode active material molded body 26. The upper surface of the positive electrode active material compact 26 is exposed from 40 (see FIG. 20).

  Thereby, the upper surface of the positive electrode active material molded body 26 is exposed from the resin composite 40 on the electrolyte layer 3, and as a result, one positive electrode active material 21 extends from the electrolyte layer 3 to one surface 51 of the positive electrode active material composite 5. Thus, the positive electrode active material composite 5 having a configuration in which the resin material is filled in the gaps formed between the positive electrode active materials 21 is formed. Therefore, in the present embodiment, a scratch mark (grinding / polishing mark) which is a trace of grinding / polishing processing is left on one surface 51 (one surface) of the positive electrode active material composite 5 to be formed.

  According to the above steps [2B-1] to [2B-4], a plurality of granular positive electrode active material particles 27 (active material particles) having a single crystal structure and in contact with the electrolyte layer 3 are arranged to form a positive electrode active material molded body 26 After forming (the active material molded body), the resin material is filled in the gaps between the adjacent positive electrode active material particles 27 to form the resin composite 40, and thereafter, the positive electrode active material particles 27 are exposed from the resin composite 40 A step of obtaining the positive electrode active material complex 5 (active material complex) is configured by polishing as described above, and the positive electrode active material complex 5 is formed on the electrolyte layer 3 through the steps.

  [3B] Next, as shown in FIG. 21, the positive electrode current collector 1 (collector electrode) is formed on the positive electrode active material complex 5 so as to be in contact with the positive electrode active material 21 exposed by the positive electrode active material complex 5 (Step S3B).

  The formation of the positive electrode current collector 1 on the positive electrode active material complex 5 can be carried out using, for example, a physical vapor deposition method such as a vacuum evaporation method or a sputtering method, or a plate, A positive electrode current collector 1 in the form of a foil, a net or the like may be prepared in advance, and then the positive electrode active material composite 5 and the positive electrode current collector 1 may be joined via an electroconductive paste. The positive electrode current collector 1 may be mechanically pressure-bonded to the composite 5.

  [4B] Next, as shown in FIG. 22, the substrate 10 is peeled off from the electrolyte layer 3 (step S4B).

  The peeling of the substrate 10 from the electrolyte layer 3 can be performed using the same method as described in the step [3A].

  In the present embodiment, the peeling of the substrate 10 from the electrolyte layer 3 is performed after the formation of the positive electrode current collector 1 described in the step [3B], but the present invention is not limited thereto. It may be carried out after the formation of the positive electrode active material complex 5 described in the step [2B].

  [5B] Next, as shown in FIG. 23, the negative electrode portion 6 is formed on the electrolyte layer 3 (step S5B).

  The formation of the negative electrode portion 6 on the electrolyte layer 3 can be performed using the same method as that described in the step [5A].

  [6B] Next, as shown in FIG. 24, the positive electrode extraction electrode 7 and the negative electrode extraction electrode 8 are formed on the positive electrode current collector 1 and the negative electrode portion 6, respectively (Step S6B).

  The formation of the positive electrode extraction electrode 7 on the positive electrode current collector 1 and the formation of the negative electrode extraction electrode 8 on the negative electrode portion 6 can be performed using the same method as that described in the step [6A]. .

  Through the steps [1B] to [6B] as described above, the lithium secondary battery 100 of the present embodiment having excellent lithium ion conductivity is manufactured.

<Electronic equipment>
Next, the electronic device of the present embodiment will be described by using a wearable device as an example. FIG. 25 is a perspective view showing a configuration of a wearable device as an electronic device of the present embodiment.

  As shown in FIG. 25, a wearable device 300 as an electronic device according to the present embodiment is an information device which is mounted like a wristwatch on, for example, a wrist WR of a human body and can obtain information related to the human body. , A sensor unit 302, a display unit 303, a processing unit 304, and a battery 305.

  The band 301 is a belt made of a flexible resin such as rubber, for example, so as to be in close contact with the wrist WR at the time of wearing, and has a joint capable of adjusting the joint position at the end of the band. .

  The sensor 302 is, for example, an optical sensor, and is disposed on the inner surface side (wrist WR side) of the band 301 so as to touch the wrist WR when worn.

  The display unit 303 is, for example, a light receiving type liquid crystal display device, and is provided on the outer surface side of the band 301 (opposite to the inner surface to which the sensor 302 is attached) so that the wearer can read the information displayed on the display unit 303. It is arranged.

  The processing unit 304 is, for example, an integrated circuit (IC), is incorporated in the band 301, and is electrically connected to the sensor 302 and the display unit 303. The processing unit 304 performs arithmetic processing for measuring a pulse, a blood glucose level, and the like based on the output from the sensor 302. Further, the display unit 303 is controlled to display a measurement result and the like.

  The battery 305 is incorporated as a power supply source for supplying power to the sensor 302, the display unit 303, the processing unit 304, and the like in a detachable state with respect to the band 301.

  As the battery 305, the lithium secondary battery 100 described in the first embodiment and the second embodiment is used. Since the lithium secondary battery 100 has excellent lithium ion conductivity, the wearable device 300 including the lithium secondary battery 100 as the battery 305 is excellent in reliability. In addition, since lithium secondary battery 100 is a solid secondary battery, it can be used repeatedly by charging, and there is no risk of leakage of an electrolyte or the like, so wearable device 300 can be used safely for a long period of time Can provide

  Further, according to the wearable device 300 of the present embodiment, the sensor 302 electrically detects the information related to the pulse and blood sugar level of the wearer from the wrist WR, etc. The pulse and blood sugar level can be displayed on the portion 303. Not only the measurement result but also, for example, information indicating the condition of the human body predicted from the measurement result and time can be displayed on the display unit 303.

  Although the wristwatch-type wearable device 300 is illustrated in the present embodiment, the wearable device 300 may be attached to, for example, an ankle, a head, an ear, a waist or the like.

  Further, the electronic device to which the lithium secondary battery 100 as a power supply source is applied is not limited to the wearable device 300. For example, a head mounted display, a head up display, a mobile telephone, a personal digital assistant, a notebook computer, a digital camera, a video camera, a music player, a wireless headphone, a game machine, etc. are mentioned. Moreover, it is applicable not only to such a consumer (general consumer) apparatus but also an apparatus for industrial use. In addition, the electronic device of the present invention may have other functions such as a data communication function, a game function, a recording and reproducing function, and a dictionary function.

  As mentioned above, although the manufacturing method of a battery concerning the present invention, a battery, and electronic equipment were explained, the present invention is not limited to this. For example, although the structure which uses an active material complex for a positive electrode was demonstrated to the example, you may use for a negative electrode. In addition, although a lithium secondary battery has been described as an example of the battery, it may be a primary battery or a secondary battery, and in particular, the secondary battery may be a battery containing an alkali metal such as a sodium battery. It is good also as a battery containing such a group 2 element (alkaline earth metal in a broad sense).

  For example, the configuration of each part in the battery of the present invention can be replaced with an arbitrary configuration having the same function. In addition, any other component may be added to the battery of the present invention.

  In addition, one or more optional steps may be added to the method of manufacturing a battery of the present invention.

DESCRIPTION OF SYMBOLS 1 ... positive electrode collector, 2 ... positive electrode active material part, 3 ... electrolyte layer, 4: resin part, 5 ... positive electrode active material composite, 6: negative electrode part, 7: positive electrode extraction electrode, 8: negative electrode extraction electrode, 10 ... Substrate, 21 ... positive electrode active material, 22 ... binder, 23 ... conductive particles, 25 ... slurry, 26 ... positive electrode active material molded body, 27 ... positive electrode active material particles, 40 ... resin complex, 41 ... resin molded body, 51: one surface, 52: other surface, 61: negative electrode active material portion, 63: negative electrode current collector, 100: lithium secondary battery, 300: wearable device, 301: band, 302: sensor, 303: display portion, 304: Processing unit, 305: battery, WR: wrist

Claims (9)

Current collector,
An active material complex including a granular active material having a single crystal structure in contact with the current collector, and a resin portion formed in a gap between the adjacent active materials;
And an electrolyte layer in contact with the active material as well as in contact with the resin portion. The battery according to claim 1, wherein the active material comprises LiCoO ₂ .   The battery according to claim 1, wherein the active material complex is in contact with the current collector and the electrolyte on a flat surface.   The battery according to any one of claims 1 to 3, wherein the resin portion is made of an epoxy resin or an acrylic resin. The battery according to any one of claims 1 to 4, wherein the ion conductivity of the resin portion is 1 × 10 ^-8 S / cm or less.   The battery according to any one of claims 1 to 5, wherein a Young's modulus of the resin portion is 15 GPa or less. Forming a current collector;
After arranging the active material particles so as to be in contact with the current collector, the resin material is filled in the gaps between the adjacent active material particles to form a resin complex, and after that, the active material particles are exposed. Obtaining an active material complex by polishing to
Forming an electrolyte layer in contact with the exposed active material particles;
A method of manufacturing a battery comprising: Forming an electrolyte layer;
After arranging the active material particles to be in contact with the electrolyte layer, the resin material is filled in the gaps between the adjacent active material particles to form a resin complex, and thereafter, the active material particles are polished to be exposed. Obtaining an active material complex by
Forming a current collector in contact with the exposed active material particles;
A method of manufacturing a battery comprising:   An electronic device comprising the battery according to any one of claims 1 to 6.

Images